Helm, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

824
FXUS66 KMFR 071118 CCA
AFDMFR

Area Forecast Discussion...CORRECTED
National Weather Service Medford OR
418 AM PDT Sat Jun 7 2025

.DISCUSSION...The skies remain clear over much ofthe area this
morning, with the exceptions of the coast and the near-shore
waters, where an extensive layer of marine stratus has pushed up
to the western slopes of the coastal ranges. These clouds should
burn off through the morning, with clear skies then expected for
nearly the entire forecast area by this afternoon.

The strong upper ridge just offshore will gradually move east
and pass over the area this weekend into early next week.
Meanwhile, the thermal trough will push inland as well, and this
will result in hot afternoon temperatures for the interior.
Afternoon highs across the area will be 15 to 20 degrees above
normal for this time of year, and some of the West Side valleys,
especially those in Josephine, Jackson, and Siskiyou counties,
could easily reach triple digits, especially Sunday and Monday.
A Heat Advisory has been issued for the valleys of those three
counties, where moderate Heat Risk values are expected. Details
can be found at PDXNPWMFR.

It will be dry most of the time and for most locations for the
majority of the forecast area, however, we are keeping a sharp eye
on the potential for thunderstorms as monsoonal moisture enters
the area late this weekend into early next week. The weak upper
low drifting offshore of California will provide a route for
moisture to stream up from the south, and when combined with the
hot daytime temperatures, moderate instability is expected to
develop by Sunday afternoon in portions of northern California,
then spread farther north into Portions of southern Oregon by
Monday. Models suggest enough instability to cover all but the
coast and the Umpqua Basin by Tuesday afternoon, when an
approaching weak upper level impulse would provide the best
chances for lift.

Sunday and Monday afternoons, instability will be marginal, with
CAPE values of up to 1000 J/kg and LIs of no less than -2. By
Tuesday, some models are bringing CAPE up to 2000 J/kg, with most
unstable LIs as low as -4. Also of note, precipitable water values
will steadily increase through Tuesday, reaching a peak of about
1.2 inches by Tuesday afternoon. With all this in mind,
thunderstorms are likely to remain sub-severe for much of the
three day event, although a few strong storms are possible with
the potential for gusty winds and small hail. The best dynamics,
lift, and moisture are available Tuesday, and this would be the
day with the best chances for more widespread thunderstorms, and
we cannot rule out an isolated near-severe storm or two. Given the
higher moisture content, some storms could also produce very
heavy rain. Stay tuned in to the latest forecast updates, as the
details on any potential storms should become more clear over the
coming days.

Ensemble means are suggesting that some form of upper level
troughing will remain overhead for the latter half of next week,
with a strong majority of ensemble members showing a large upper
level low or open trough moving into the area Fathers Day
weekend. This would result in cooler temperatures and additional
chances for showers and thunderstorms during the remainder of the
forecast, especially next weekend. -BPN


&&

.AVIATION...06/12Z TAFs...Marine stratus has returned to the coast,
with IFR/LIFR ceilings reported at KOTH and observed in most coastal
valleys and across the near shore waters. These areas should clear
to VFR by midday, but MVFR/IFR conditions will likely return to
the same areas this evening and tonight. VFR prevails elsewhere
with light winds. Winds become gusty later this morning and this
afternoon at the coast with other areas seeing typical afternoon
breezes. -Hermansen/BPN

&&

.MARINE...Updated 200 AM Saturday, June 7, 2025...Gusty north winds
and steep seas continue across area waters, with the strongest winds
south of Cape Blanco. The thermal trough will gradually weaken
today, with conditions slowly improving through tonight and
relatively calm conditions expected tonight into Monday.

The thermal trough returns Tuesday, with gusty north winds and steep
to very steep seas then continuing through much of the week. -BPN

&&



.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Heat Advisory from 11 AM Sunday to 8 PM PDT Monday for ORZ024-
     026.

CA...Heat Advisory from 11 AM Sunday to 8 PM PDT Monday for CAZ080-
     081.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT this
     evening for PZZ356-376.

     Small Craft Advisory until 11 PM PDT this evening for PZZ350-
     370.

&&

$$